Berzelius carefully studied atomic weights of elements, using oxygen as a standard against other elements. His findings, first published in 1818 and revised in 1826, are incredibly accurate. This work of his contributed to the later development of the modern atomic theory.

Berzelius was born and grew up in Göttland, Sweden. Although he was close to failing his medical studies at the University of Uppsala, he received an M.D. (medicinae doctor, doctor of medicine) degree in 1802 and became a professor at the same university in 1807. The year after, Berzelius was elected to the Stockholm Royal Academy of Science. Later he became a professor of chemistry at the Royal Caroline Meidoc-Chirugical Institute in Stockholm.